The invention relates to orthodontic treatment and more particularly to arrangements for applying pressure to an orthodontic arch with posterior neck strap type headgear.
For orthodontic treatment, an orthodontic appliance such as a face bow is commonly used to apply forces for tooth or alveolar bone repositioning. A face bow generally has an inner bow mountable to bands attached to selected posterior teeth of a patient and an outer bow connected to the inner bow. The attached outer bow extends around and outside on opposite sides of the patient""s cheeks. Ends of the outer bow may be detachably secured to a headgear arrangement such as a posterior neck strap. The headgear has one or more tension supplying members such as a spring type device which are connected to the outer bow ends by strap sections extending around the patient""s neck. The force applied to the face bow during orthodontic adjustment by the headgear varies and may be adjusted during treatment by changing settings on the tension supplying member or by rearranging the strap sections connecting the tension supplying member to the outer bow.
According to accepted practice, the tension supplied to the appliance (e.g., a neck or cervical head-gear unit) is adjusted under supervision of an orthodontic practitioner during a sequence of office visits. The amount of force applied to the face bow by the neck head-gear unit is initially set for a prescribed interval by the orthodontic practitioner. The neck strap of the headgear is then modified to successively increase the applied force at intervals determined by the orthodontic practitioner. In order for the orthodontic provider to make the force adjustment, the neck strap may include a structure to allow the ends of the outer bow to be attached at varying positions along the strap.
FIG. 1 shows an arrangement of headgear on a patient having uniformly spaced apertures for tension adjustment according to the prior art as disclosed, for example, in U.S. Pat. No. 5,030,088 to S Rogow on Jul. 9, 1991. Referring to FIG. 1, there is shown a neck strap 100 that includes a neck band section 101, a force producing device 120 on the neck band a position adjustment strap section 105 connected to the force producing device 120, adjustment apertures 115-1, 115-2 and 115-3, . . . 115-n in the strap section 105 and a tie rod 110 that is connected to an inner face bow (not shown). During treatment, the tie rod 110 may be initially secured in the aperture 115-1 to apply a first force. In order to increase the force for tooth or mouth positioning, the tie rod is moved as determined by the orthodontic practitioner through the sequence of apertures 115-1 through 115-n. The selection of an aperture of the sequence in FIG. 1 to connect the face bow is reevaluated by the orthodontic practitioner during periodic visits by the patient usually every three or four weeks. Neck straps of headgear as exemplified in FIG. 1 are made with uniformly spaced apertures to aid the orthodontic practitioner in setting the adjustment positions for the patient. It would be advantageous to provide a headgear structure adapted to provide a comfortable, rapid build up of neck strap tension in small increments between visits to the orthodontic practitioner and to have the patient or the patient""s caregiver provide the sequence of comfortable, rapid build-up adjustments without consultation with the orthodontic practitioner.
The invention is directed to orthodontic treatment in which tension is applied to an orthodontic appliance by a tension supplying member. A first adjustment arm is connected to one end of the tension supplying member and a second adjustment arm is connected to the other end of the tension supplying member. A first connecting member connects the first adjustment arm to one mouth connecting element of orthodontic appliance and a second connecting member connects the second adjustment arm to another mouth connecting element of the orthodontic appliance.
According to the invention, the second adjustment arm includes a series of indicated positions along its length to which the one end of the second connecting member is engaged. Each indicated position corresponds to application of a prescribed tension to the orthodontic appliance assigned for use during a selected period of orthodontic treatment. The second connection member engages the second adjustment arm at succeeding indicated positions of the sequence to increase the prescribed tension according to a pre-assigned schedule of orthodontic adjustment.
According to an aspect of the invention, each indicated position includes a mark along the length of the second adjustment arm.
According to another aspect of the invention, the marks are differentiated by color according to the pre-assigned schedule of treatment.
According to yet another aspect of the invention, the second connection member engages an element of the orthodontic appliance and engages the second adjustment arm at one of the indicated positions selected according to the pre-assigned schedule.
According to yet another aspect of the invention, the first connecting member engages the first adjustment arm at a position for providing a first prescribed tension for orthodontic treatment when the second connection member engages the second adjustment arm at the first indicated position furthest from the tension supplying member.
According to yet another aspect of the invention, the spacing between the successive indicated positions is set according to the pre-assigned schedule of orthodontic adjustment.
According to yet another aspect of the invention, the sequence of indicated positions on the second adjustment arm includes a sequence of at least first, second, third, fourth and fifth indicated positions in that order with the first indicating position being furthest from the tension supplying member. The spacing between the first and second indicated positions is greater than the spacing between the second and third indicated positions. The spacing between the second and third indicated positions is greater than the spacing between the third and fourth indicated positions and the spacing between third and fourth indicated positions is greater than the spacing between the fourth and fifth indicated positions.
According to yet another aspect of the invention, at least the first, second, third and fourth indicated positions are differentiated by color.
According to yet another aspect of the invention, the second adjustment arm includes a series of indentations along its length. Each indicated position is set in one of the indentations. The second connecting member is inserted into the indentations for the indicated positions according to the pre-assigned schedule and engages the another element of the orthodontic appliance.
According to still yet another aspect of the invention, the tension supplying member is an elastic unit connected between the first and second adjustment arms. The elastic unit may be a coiled spring.
In an embodiment of the invention, a coiled spring in a plastic tube that supplies tension is connected between first and second elongated strap type adjustment arms. The second elongated strap has a sequence of marked positions along its length. A first connection device is detachably engaged with one outer bow end of a face bow and is slidably clamped at a position along the length of the first elongated strap type adjustment arm. A second connection device is detachably engaged with the other outer bow end of the face bow and is slidably clamped at one of the marked positions along the length of the second elongated strap type adjustment arm. The marked positions on the second elongated strap are spaced apart to provide a prescribed sequence of increased tension during successive periods of orthodontic adjustment according to a pre-assigned schedule.
The first position on the second elongated strap nearest its unattached end may be indicated by a black mark. The second position is spaced a prescribed distance from the first position and may be indicated by a blue mark. The third position is spaced from the second mark by a smaller than first to second mark distance and is indicated by a green mark. The fourth position is spaced from the third mark by a smaller than second to third mark distance and is indicated by a yellow mark. The fifth position is spaced from the fourth mark by a smaller than third to fourth mark distance and is indicated by a red mark. Sixth and succeeding positions are uniformly spaced and are indicated by red marks. The sixth and succeeding positions are equally spaced apart by a distance equal to the distance between the fifth and the sixth marks. The spacing between marked positions are precisely determined according to a prescribed course of orthodontic adjustment. For example, movement from one indentation to the next indentation may increase tension by 25 to 30 grams. During treatment, the patient wears the headgear connected to the orthodontic appliance at least for overnight periods and for a child, two or three hours after school.
At the start of an initial period of adjustment, the second connection device is clamped to the first position (black) in from the outer bow on the second elongated strap and the first connection device is clamped at a position on the first elongated strap so that a first tension for the initial period of orthodontic adjustment (e.g., comfortable tension) is applied to the face bow. At the end of the initial orthodontic adjustment period, the second connection device is moved to the second position (blue) on the second elongated strap to increase the tension on the face bow to that prescribed for the second orthodontic treatment period. In the third orthodontic treatment period, the second connection device is clamped at the third position (green) to supply an increased prescribed tension. For the fourth orthodontic adjustment period, the second connection device is clamped at the fourth position (yellow) to supply an increased prescribed tension. For the succeeding periods of orthodontic treatment, the second connection member is sequentially moved to succeeding positions (red) so that the prescribed tension is incrementally increased a prescribed amount (e.g., 25-30 grams). Between the initial positioning and the last adjustment period of a sequence, the tension adjustment may be performed by the patient or the patient""s caregiver according to the pre-assigned schedule under prescribed conditions preset by the orthodontic practitioner.
The invention will be better understood from the following more detailed description taken together with the accompanying drawings and the claims.